MESOSCALE PRECIPITATION DISCUSSION 0320
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
652 PM EDT TUE JUN 13 2017

AREAS AFFECTED...FAR SOUTHERN ND...CENTRAL/EASTERN SD...NORTHERN
NEB

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 132251Z - 140230Z

SUMMARY...FLASH FLOODING IS POSSIBLE OVER PARTS OF NEBRASKA AND
SOUTH DAKOTA AND A SMALL PORTION OF NORTH DAKOTA WHERE CELLS THAT
PRODUCE HEAVY RAINFALL TRAIN OVER THE SAME AREA. HOURLY RAIN RATES
UP TO 2" WITH LOCALLY HIGHER AMOUNTS ARE POSSIBLE INTO THE EARLY
EVENING HOURS.

DISCUSSION...THUNDERSTORMS WERE DEVELOPING ALONG AN AXIS OF
PRECIPITABLE WATER VALUES AT OR ABOVE 1.5 INCHES AND A REGION
WHERE THE SURFACE DEWPOINT WAS RUNNING CLOSE TO 70 DEGREES.  THE
FLOW ALOFT OVER THIS REGION IS PREDOMINANTELY FROM THE SOUTH
ACROSS THE PLAINS AND THEN BECOMES INCREASINGLY DIFLUENT OVER THE
DAKOTAS.  GIVEN SLOW EASTWARD TRANSATION WITH TIME...THE POTENTIAL
EXISTS FOR SOME FLASH FLOODING AS NEW CELLS FORM AND TRAIN OVER
AREAS WHICH HAVE ALREADY RECEIVED HEAVY RAINFALL.

HIGHEST RAINFALL RATES SHOULD BE FOCUSED MORE IN THE SOUTHERN
PARTS OF SOUTH DAKOTA AND NORTHERN NEBRASKA WHERE FFG VALUES ARE
CLOSE TO 3 INCHES PER 3 HOURS.  TO THE NORTH...CAPES AND
ASSOCIATED RAFL RATES WILL PROBABLY NOT BE QUITE AS HIGH BUT FLASH
FLOOD GUIDANCE IS ON THE ORDER OF 1.5 TO 2 INCHES PER 3 HOURS.

BANN

ATTN...WFO...ABR...BIS...FSD...LBF...OAX...

ATTN...RFC...MBRFC...

LAT...LON   46229991 45899822 45029737 43129785 42379883
            42469939 43129925 43729922 44419927 45309978